Characteristics of Four Upward-Pointing Cosmic-Ray-like Events Observed with ANITA

• Main Authors: Gorham, PW, Nam, J, Romero-Wolf, A, Hoover, S, Allison, P, Banerjee, O, Beatty, JJ, Belov, K, Besson, DZ, Binns, WR, Bugaev, V, Cao, P, Chen, C, Chen, P, Clem, JM, Connolly, A, Dailey, B, Deaconu, C, Cremonesi, L, Dowkontt, PF, Duvernois, MA, Field, RC, Fox, BD, Goldstein, D, Gordon, J, Hast, C, Hebert, CL, Hill, B, Hughes, K, Hupe, R, Israel, MH, Javaid, A, Kowalski, J, Lam, J, Learned, JG, Liewer, KM, Liu, TC, Link, JT, Lusczek, E, Matsuno, S, Mercurio, BC, Miki, C, Miočinović, P, Mottram, M, Mulrey, K, Naudet, CJ, Ng, J, Nichol, RJ, Palladino, K, Rauch, BF, Reil, K, Roberts, J, Rosen, M, Rotter, B, Russell, J, Ruckman, L, Saltzberg, D, Seckel, D, Schoorlemmer, H, Stafford, S, Stockham, J, Stockham, M, Strutt, B, Tatem, K, Varner, GS, Vieregg, AG, Walz, D, Wissel, SA, Wu, F
• Format: Article in Journal/Newspaper
• Language: English
• Published: 2016
• Subjects: Antarctic; The Antarctic; Antarc*
• Online Access: https://discovery.ucl.ac.uk/id/eprint/1486406/1/Gorham_Characteristics%20of%20Four%20Upward-Pointing%20Cosmic-Ray-like%20Events%20Observed%20with%20ANITAVOR.pdf; https://discovery.ucl.ac.uk/id/eprint/1486406/

We report on four radio-detected cosmic-ray (CR) or CR-like events observed with the Antarctic Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration balloon payload. Two of the four were previously identified as stratospheric CR air showers during the ANITA-I flight. A third stratospheric CR was detected during the ANITA-II flight. Here, we report on characteristics of these three unusual CR events, which develop nearly horizontally, 20-30 km above the surface of Earth. In addition, we report on a fourth steeply upward-pointing ANITA-I CR-like radio event which has characteristics consistent with a primary that emerged from the surface of the ice. This suggests a possible τ-lepton decay as the origin of this event, but such an interpretation would require significant suppression of the standard model τ-neutrino cross section.